Error while connecting SUT as webdriver

Hi Everyone,
Am trying to connect my SUT as ‘WebDriver’, but am getting error as
"WebDriver Connect Failed: A connection attempt failed because the third party connection did not properly respond after a period of time, or established connection failed because connected host as failed to respond."
Steps i have follwed prior this.
1. Installed Webdriver.exe from testplant downloads, and it is running in SUT before hitting to connect.
Please let me know if steps followed are wrong or any additional is required.
Please do suggest me ASAP… Thank you…